#include<stdio.h>

int main()
{
    int a = 21;
    int b = 10;
    int c ;

    c = a + b;
    printf("Line 1 - c的值是%d\n", c);
    c = a - b;
    printf("Line 2 -c 的值是%d\n", c);
    c = a * b;
    printf("Line 3 - c 的值是%d\n",c);
    c = a / b;
    printf("Line 4 - c 的值是%d\n", c);
    c = a % b;
    printf("Line 5 - c 的值是%d\n", c);
    c = a ++; //赋值后再加1， c为21， a为22
    printf("Line 6 - c 的值是%d\n", c);
    c = a --; //赋值后再减1， c为22，a 为21
    printf("Line 7 - c 的值是%d\n", c);
}